Currently surgeons employ medical instruments that deliver energy in the treatment of benign prostatic hyperplasia, which is commonly referred to as BPH. BPH is a condition of an enlarged prostate gland, in which the gland having BPH typically increases beyond its normal size. Methods generally known as Interstitial Thermotherapy (ITT), and specifically Laser Interstitial Thermotherapy, sometimes referred to as LITT, have been widely used in the treatment of this condition. ITT utilizes energy delivery devices, often in the form of LITT using laser light sources, to treat the BPH condition using optical fibers that emit light radially in a predictable and controlled manner. The goal of LITT is to diffuse light into the human tissue in a controlled manner in order to coagulate or ablate the tissue, thus decreasing the volume of the gland and alleviating the symptoms of BPH. Similar devices are also used for Photo-Dynamic Therapy (PDT), wherein a light-activated pharmaceutical agent is used in combination with diffusing fibers to treat human diseases.
During the treatment of human tissue by LITT, accurately controlling the amount of energy diffused through the optical fiber and absorbed by the human tissue is critical to assure efficacious treatment. The amount of energy absorbed by the human tissue can be monitored by measuring the temperature at the treatment site. Even minor variations in temperature at the location being treated can change the therapeutic benefits of treatment. One difficulty with the use of fiberoptic technology to deliver energy is that the performance of the materials used to construct the fiberoptic may change with use or age. These performance changes can result in variations in the amount of energy transmission through the optical fiber, which may lead to over or under-treatment of the tissue. However, accurate measurement of the tissue temperature at the treatment site can be used to detect performance changes of the optical fiber. In particular, any inconsistencies or shifts in the tissue temperature may indicate unwanted variations in energy delivery that may lead to over treatment or under treatment of the tissue, which can result in an inferior clinical outcome.
Additionally, some fiber optic devices may be damaged or degraded as a result of the mechanical or thermal stresses incident to normal use. Excessive bending, pulling, flexing, manipulating, twisting or heating can cause changes in the performance of the fiberoptic. Even ordinary and expected usage can affect the energy delivered through the fiber optic device over an extended period of time. Use of a fiber optic device or in excess of its design expectancy or useful life can also result in further degradation of the optical fiber.
It is desirable to limit the use of the fiberoptic device based upon the extent of use or overall age of the device. By restricting the use of the device to within expected design limits, performance changes of the fiberoptic may be avoided, and the risk of a malfunction may be decreased.
Consequently, there is a need for specific medical treatment systems that prevent reuse upon detecting degradation of the optical fiber or when the expected life limits of the optical fiber have been exceeded. There is also a need for such devices that provide for monitoring of temperatures at the treatment site while also providing for limitations on reuse or overuse by giving full consideration to the multiplicity of diverse factors that can detect performance changes of the fiber optic device. Such an apparatus and methodology will help assure that fiber optic devices are not utilized in excess of their designed or useful life, and this will also help practitioners to assure that patients receive the most efficacious treatment that these devices can provide.